I'm pretty familiar with what's available for FE intakes. The adapter is a nice piece, but not one of the intakes that work with it are made for an FE so I'll stand by my statement. I don't even consider a $650.00 adapter, so I can use another $4-500.00 intake, a viable option. Like I said, not many GOOD intakes made for an FE. Lots of 60's technology. About the only real "modern" intake for teh FE is the Edelbrock Victor and it's hardly modern. The design has it's limitations.
Just to correct any misconceptions, my intake adapters are $569, not $650, assuming you buy them through my web site (not ebay). No one has done more FE intake testing than me, and after all the intake testing I've done, I'm confident in saying that the adapter plus a 351C Weiand tunnel ram is top of the mark for an FE intake. There is nothing better (outside of a sheet metal manifold), and that includes a tunnel wedge or a Victor. Plus, there are other advantages of the adapter, including options to use intakes that are just not available for the FE (the Trick Flow EFI intakes come to mind), access to the valley without removing the valve covers, distributor, or breaking the water jacket, better clearance to the pushrods (or custom pushrod hole locations, if you need that), custom porting options, and ease of swapping from one intake to another. Its true that the adapter plus a 351C intake is going to be more expensive than a straight up FE intake like a Performer RPM or a Victor, but it would actually be cheaper than a lot of the older intakes that you see advertised (the crossram intakes and factory tunnel wedge intakes come to mind). Induction systems can get expensive for the FE; we don't have the options that more mainstream engines have. As a result the intake adapter fills a niche for FE enthusiasts, and offers intake flexibility that otherwise wouldn't exist.